Re: [PATCH v2 0/9] thermal/core: Protect thermal device operations against removal

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Nov 14, 2022 at 07:06:57PM +0100, Rafael J. Wysocki wrote:
> On Thu, Nov 10, 2022 at 4:25 PM Guenter Roeck <linux@roeck-us.net> wrote:
> >
> > Accesses to thermal zones, and with it to thermal zone device operations,
> > are still possible after the thermal zone device has been unregistered.
> > For example, thermal_zone_get_temp() can be called from temp_show()
> > in thermal_sysfs.c if the sysfs attribute was opened before the thermal
> > device was unregistered. This is problematic and may result in crashes
> > since the operations data structure and the underlying code may be gone
> > when the calls are made.
> >
> > The following series solves the problem by protecting accesses to thermal
> > device operations with the thermal device mutex, and by verifying that the
> > thermal device is still registered after the mutex has been acquired.
> >
> > This was previously sent as RFC/RFT as single patch [1]. The code was reworked
> > to match thermal subsystem changes made between v6.0 and v6.1, and it was
> > split into several patches to simplify review.
> >
> > [1] https://lore.kernel.org/linux-pm/20221004033936.1047691-1-linux@roeck-us.net/
> >
> > v2: Improved documentation, rearranged code.
> >     No functional changes. See individual patches for details.
> >
> > ----------------------------------------------------------------
> > Guenter Roeck (9):
> >       thermal/core: Destroy thermal zone device mutex in release function
> >       thermal/core: Delete device under thermal device zone lock
> >       thermal/core: Ensure that thermal device is registered in thermal_zone_get_temp
> >       thermal/core: Move parameter validation from __thermal_zone_get_temp to thermal_zone_get_temp
> >       thermal/core: Introduce locked version of thermal_zone_device_update
> >       thermal/core: Protect hwmon accesses to thermal operations with thermal zone mutex
> >       thermal/core: Protect sysfs accesses to thermal operations with thermal zone mutex
> >       thermal/core: Remove thermal_zone_set_trips()
> >       thermal/core: Protect thermal device operations against thermal device removal
> >
> >  drivers/thermal/thermal_core.c    | 76 +++++++++++++++++++++++--------------
> >  drivers/thermal/thermal_core.h    |  3 +-
> >  drivers/thermal/thermal_helpers.c | 67 +++++++++++++++++++++------------
> >  drivers/thermal/thermal_hwmon.c   | 10 ++++-
> >  drivers/thermal/thermal_sysfs.c   | 79 ++++++++++++++++++++++++++++++++-------
> >  5 files changed, 168 insertions(+), 67 deletions(-)
> 
> All applied as 6.2 material, thanks!

Thanks a lot!

Guenter